Hard rock mined ore truck body

ABSTRACT

A truck body designed for transporting hard rock mined ore. The truck body includes a body floor having a first material forming a floor structure and a liner structure including a second material covering at least a portion of the floor structure. The second material has a hardness that is greater than a hardness of the first material and prevents wear of the truck body floor by the hard rock ore. The truck body includes a front wall and two opposing body sidewalls that taper outwardly from front to rear of the truck body such that a width between the body sidewalls at a rear of the truck body is at least 10% greater than a width at the front of the truck body. The outward tapering of the body sidewalls promotes movement of the load away from the body sidewalls as the load is released from the truck body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/654,157, filed on Oct. 17, 2012, which claims the benefit of U.S.Provisional Patent Application No. 61/548,136, filed Oct. 17, 2011,which is incorporated by reference.

TECHNICAL FIELD OF THE INVENTION

This invention generally relates to a truck body and more particularlyto a truck body for hauling mined ores such as iron ore and othersimilar “hard rock mineral” ores. This invention further relates to boththe design of an truck body and the use of certain highly wear resistantmaterials in combination with the truck body design to produce asuperior Hard Rock Mined Ore Truck Body for transporting “hard rock”mined ores like iron ore in an iron ore mine, copper ore in a coppermine, and other similar hard rock mineral ores.

BACKGROUND OF THE INVENTION

Referring specifically to iron ore, iron is the world's most commonlyused metal “steel” of which iron ore is the key ingredient, representingalmost 95% of all metal used in a year.

Iron ore is the raw material used to make pig iron, which is one of themain raw materials used to make steel. 98% of the mined iron ore is usedto make steel. In fact, iron ore is more integral to the world's economythan any other commodity except oil/fuel.

The principle ores of iron are hematite (70% iron) and magnetite (72%iron). Ore is typically found in magnetite and hematite minerals.Hematite is an iron oxide as is magnetite.

Initially, iron ore was predominately mined from hematite deposits withgrades in excess of 60% iron. Such deposits are commonly referred to as“direct shipping ores” or “natural ores”. With depletion over time ofhigh grade hematite deposits, lower grade ores have been furtherdeveloped. This development of lower grade iron ores has led to thedevelopment of taconite iron ore.

Taconite is a “low grade” iron ore, only containing about 30%magnetite/hematite. This taconite iron ore comprises only smallparticles of magnetite and hematite interspersed with a very toughvariety of quartz—chert. Chert is an extremely hard abrasive mineral.

To measure, in a relative way, the hardness of various materials such aschert, magnetite, hematite and other minerals, the Mohs scale, arelative measurement tool, was created in 1812 by the German geologistand mineralogist Friedrich Mohs. The Mohs scale of mineral hardnesscharacterizes the scratch resistance of various minerals through theability of a harder material to scratch a softer material.

The basic premise behind the Mohs scale is that, in order to identify(or bracket) the hardness (abrasion resistance) of a material an attemptis made to scratch a sample of the material with various materialslisted on the Mohs scale of materials, until a particular material onthe Mohs scale is identified that will scratch the sample of unknownmaterial, while the Mohs scale “control” material is not scratched.

This same premise applies to truck bodies. As long as the materialforming the truck body is higher on the Mohs scale than the materialbeing hauled, there will be little to any abrading away (abrasion) ofthe load containing surfaces of the truck body. However, if the materialbeing hauled in the truck body is higher on the Mohs scale than thematerial forming the truck body, then the floor, side plates, etc. ofthe truck body will be worn away (abraded) with every load hauled.

The original Mohs scale comprised the hardness/abrasion resistancenumbers 1 thru 10, with 1 being the softest and 10 being the hardest, asshown in Table 1 below. Alternative Vickers hardness numbers (HV)(another way of comparing relative material hardenesses) are also shownby comparison.

TABLE 1 Mohs scale of mineral hardness Mineral Mohs Hardness Vickers HVTalc 1  20 HV Gypsum 2  70 HV Calcite 3  110 HV Fluorite 4  180 HVApatite 5  500 HV Orthoclase 6  720 HV Quartz 7 1280 HV ChromiumCarbides — 1500 HV Topaz 8 1620 HV Molybdenum Carbides — 1800 HVCorundum 9 2000 HV Titanium Carbides — 3000 HV Diamond 10  9000 HV

Over time the ten items first identified in the Mohs scale, which reallyonly denotes relative hardness, required expanding to a more definedcomparative hardness level and the Vickers scale was introduced to moreclearly delineate relative hardness of materials.

The hardness of a material is further defined as the material'sresistance to another material penetrating the material's surface and isrelated to the material's abrasion/wear resistance and strength. Higherhardness is generally related to higher strength, which in turn isrelated to the material's structure.

The Vickers hardness is defined by test standards, and requires a squarepyramid indenter made of diamond to be pressed into a test sample at aspecified load. The resulting indentation is then measured from tip totip in both axes. The average measurement is converted to a Vickershardness value according to a formula or a chart based on the formula.

Table 2 is a comparison between the Mohs number for various materialsand a Vickers hardness number.

TABLE 2 Comparison of Mohs hardness and Vickers hardness for variousmaterials Mineral Name Hardness (Mohs) Hardness (Vickers) kg/mm²Graphite   1-2 VHN₁₀ = 7-11 Tin 1½-2 VHN₁₀ = 7-9 Bismuth     2-2½ VHN₁₀₀= 16-18 Gold 2½-3 VHN₁₀ = 30-34 Silver 2½-3 VHN₁₀₀ = 61-65 Chalcocite2½-3 VHN₁₀₀ = 84-87 Copper 2½-3 VHN₁₀₀ = 77-99 Galena 2½ VHN₁₀₀ = 79-104Sphalerite 3½-4 VHN₁₀₀ = 208-224 Heazlewoodite 4 VHN₁₀₀ = 230-254Carrollite   4½-5½ VHN₁₀₀ = 507-586 Goethite     5-5½ VHN₁₀₀ = 667Hematite   5-6 VHN₁₀₀ = 1,000-1,100 Chromite   5½ VHN₁₀₀ = 1,278-1,456Anatase 5½-6 VHN₁₀₀ = 616-698 Rutile     6-6½ VHN₁₀₀ = 894-974 Pyrite    6-6½ VHN₁₀₀ = 1,505-1,520 Bowieite 1 VHN₁₀₀ = 858-1,288 Euclase   7½VHN₁₀₀ = 1,310 Chromium 9 VHN₁₀₀ = 1,875-2,000

Referring specifically to iron ore, on the Mohs scale and on the Vickershardness scale, the basic components of taconite iron ore are shown inTable 3.

TABLE 3 Mohs hardness and Vickers hardness for components of taconiteiron ore Mineral Name Hardness (Mohs) Hardness (Vickers) Hermatite 5.5to 6.5+ 1,000 to 1,100 Magnetite 6.5+ 1,100 Quartz (chert) 7 1275

Referring to the steels used in producing truck bodies, typical highstrength, high hardness steel used today in producing truck bodies has abasic maximum hardness of 450 Brinell. (The Brinell scale being theindustry standard for hardness calculations of steel in this field.) Insome highly abrasive truck body applications, a high hardness 600Brinell steel or higher with minimal structural strength characteristicscan also be used.

Having introduced Brinell along with the previously described Mohs scaleand Vickers scale, it is important to understand the relationshipbetween the following three material measurements:

1. Mohs Scale

2. Vickers

3. Brinell

The Vickers HV number is determined by the ratio F to A where “F” is theforce applied to the material, and “A” is the surface area of theresulting indentation. The Vickers is used as an alternative to theBrinell method, and is different than the Mohs hardness scale whichtests a material's scratch resistance.

The Brinell hardness scale is very similar to the Vickers hardness scaleand was developed by a Swedish engineer named Johan August Brinell in1900. The Brinell test utilizes a 10 mm diameter steel ball as anindenter, applying a uniform 3,000 kgf (29 kN) force. (A smaller amountof force is used on softer materials, and a tungsten carbide ball isused for harder materials.)

With the Mohs scale, the hardness of a sample is measured againststandard test materials by finding the hardest material the sample canscratch, and/or by identifying the softest test material that canscratch the sample. For example, if a given sample can be scratched byquartz (Mohs 7) but not by topaz (Mohs 8), the sample has a hardnessbetween 7 and 8 and is possibly about 7.5 on the Mohs scale.

TABLE 4 Comparison of Vickers and Brinell Brinell Hardness VickersHardness 10 mm tungsten carbide ball — Load 3000 kg 940 — 920 — 880(767) 840 (745) 800 (722) 760 (698) 720 (670) 690 (647) 670 (630) 650611 630 591 610 573 590 554 570 535 550 517 520 488 500 471 480 452 460433 440 415 420 397

It is readily apparent from Table 4 that the 450 Brinell high strength,high hardness steel commonly used in the manufacture of truck bodies has(only) a Vickers number of 480 and from Table 2 a corresponding Mohsscale number of about 4.75 which is far below the Vickers number of1,000 to 1,275 (see Table 3) of hauled hard rock mineral ores such asiron ore and/or similar hard rock ores.

And, just as iron ore has a higher Vickers number than that of the highstrength/high hardness steels commonly used to produce a typical truckbody, there are many other mined hard rock ores that also have higherVickers numbers than those of the steels used to produce conventionaltruck bodies.

SUMMARY OF THE INVENTION

An aspect of the present invention is to provide a truck body capable ofhauling hard rock mineral ore without being susceptible to high abrasionrates. In particular, the truck body is adapted to haul materials havinghardnesses that are greater than that of steel typically used for thestructural components of truck bodies, for example, materials having ahardness that is higher than 450 or 600 Brinell (Vickers 480 or 630).

This aspect of the invention can be achieved by a truck body including acombination of features adapted to prevent abrasion of the loadcontaining surfaces of the truck body.

First, the truck body floor, which is inevitably subjected to contactwith hard rock material as it slides and is dumped from the truck body,is provided with a liner structure made of a material having a hardnessthat is higher than the hardness of the underlying floor surface andthat is also higher in hardness than the hard rock mined ore. Due to thehardness of the liner structure, the truck body floor is protected fromabrasion as the hard rock mined ore slides from truck body floor when itis dumped.

The truck body also includes body sidewalls having an extreme outwardtaper from the front of the truck body to the rear of the truck body.For example, the tapering of the body sidewalls results in a rear truckbody sidewall width that is at least 10% greater than the body sidewallwidth at the front of the truck body. As a result of the outward bodysidewall taper from the front of the truck body to the rear of the body,the hauled material effectively recedes from the body sidewalls as itslides from the truck body as the load is dumped. The relative movementof the load away from the body sidewalls prevents the hauled materialfrom scraping against the body sidewalls during dumping. Accordingly,this body sidewall tapering provides an effective means to preventabrasion of the truck body sidewalls.

In an embodiment, the present invention provides a truck body fortransporting hard rock mined ore. The truck body includes a body floorhaving an edge at which the hard rock mined ore loaded into the body isreleased when the body is moved into a dumping position. The body floorincludes a first material forming a body floor structure and a secondmaterial forming a liner structure covering at least a portion of thebody floor structure. The second material has a hardness that is higherthan a hardness of the first material, such that the liner structureprotects the body floor structure from abrasion during load dumping. Abody front wall confines a load of the hard rock mined ore at a front ofthe truck body and two opposing body sidewalls confine the load atopposing sides of the truck body. The body sidewalls taper outwardlyfrom front to rear of the truck body such that the width between thebody sidewalls at the rear of the truck body is at least 10% wider thanthe width between the body sidewalls at the front of the truck body. Theoutward tapering of the body sidewalls promotes movement of the loadaway from the body sidewalls as the load is dumped from the truck body,thereby minimizing abrasion of the truck body sidewalls during dumping.

In another embodiment, the present invention provides a method oftransporting hard rock mined ore using a truck. A load of hard rockmined ore including a material having a high hardness is deposited intoa truck body. The truck body includes a floor having an edge at whichthe load of hard rock mined ore in the truck body is released when thebody is moved into a dumping position and includes a first materialforming the truck body floor structure that has a hardness below thehauled hard rock mined ore hardness and a body liner structure of asecond material with a hardness that is greater than the hauled hardrock mined ore hardness and that covers at least a portion of the truckbody floor surface. A truck body front wall confines the load of hardrock mined ore at the front of the truck body and two opposing bodysidewalls confine the load at the sides of the truck body. The bodysidewalls taper outwardly from front to rear of the truck body such thatthe width between the truck body sidewalls is at least 10% greater atthe rear of the truck body than at the front of the truck body. Indumping, as the truck body is pivoted upward the load of hard rock minedore slides out of the truck body while the outward tapering bodysidewalls confining the load recede away from the load thus sliding out.The outwardly tapering body sidewalls minimize abrasion of the bodysidewalls by the hard rock mined ore. Further, the floor surface of thetruck body floor is protected from abrasion by the body liner structure.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention are described in moredetail below, with reference to the drawings, in which:

FIG. 1 is a side view of a truck for hauling materials with the truckbody in a lowered position;

FIG. 2 is the truck of FIG. 1 with the truck body in a raised position;

FIG. 3 is top view of a truck body illustrating an outward tapering ofthe body sidewalls;

FIG. 4a is a top view of the truck body illustrating a liner structureon the truck body floor;

FIG. 4b is a perspective detail view of an intersection between thetruck body sidewall and truck body floor;

FIG. 4c is a perspective detail view of a liner structure on the truckbody floor;

FIG. 5 is a top view of a truck body with an alternative liner structureconfiguration;

FIG. 6 is a top view of a truck body with another alternative linerstructure configuration;

FIG. 7 is a top view of a truck body with yet another alternative linerstructure configuration; and

FIG. 8 is a top view of a truck body with a liner structure and anon-stick surface bridging an intersection between the body floor, bodyfront wall and body sidewall; and

FIG. 9 is a flow chart showing a method of making and using a truck bodyfor transporting hard rock mined ore.

DETAILED DESCRIPTION

FIGS. 1-8 illustrate various embodiments of a specially designed truckbody configured to haul materials of a sufficient hardness to causerapid abrasion of the load containment surfaces of an ordinary truckbody. Each of the illustrated embodiments combines the use of a linerstructure on at least a portion of the truck body floor to preventabrasion of the floor surface along with an extreme outward tapering ofthe body sidewalls from the front to the rear of the truck body. Theresulting truck bodies are protected from abrasion on the truck bodyfloor by the robust floor liner structure and, due to the outwardtapering body sidewalls, are protected from abrasion on the bodysidewalls by avoiding contact with the hauled materials during loaddumping.

Referring to FIG. 1, a vehicle 100 for hauling hard rock mined oreincludes a frame 102 supported by wheels 104 configured to transport thevehicle between loading sites and dumping sites. A truck body 2 issupported on the frame and is specifically constructed for carrying hardrock mined ores without being subject to rapid abrasion, as explained inmore detail above. The truck body 2 is fixed on the frame 102 at a pivotpoint 106 toward the rear of the vehicle and can be rotated as shown inFIG. 2, about the pivot point 106 by hydraulic cylinders 108 (one shown)that lift the front end of the truck body 2. As a result, material thathas been loaded into the truck body 2 is dumped from the rear of thetruck body 2 when the truck body is raised. Operation of the vehicle,including vehicle movement and truck body raising and lowering asperformed by an operator seated in the cab 110 at the front of thevehicle.

Referring to FIG. 3, a truck body 2 includes a body floor 4, twosidewalls 6 and a front wall 8. A canopy 10 extends forward from the topof the truck body front wall 8 and is configured to cover the front ofthe corresponding truck chassis, particularly the cab. The sidewalls 6of the truck body 2 taper outwardly from the front 12 to the rear 14 ofthe truck body 2. A liner structure 20 covers a portion of the truckbody floor 4, as will be described in greater detail below.

To prevent abrasion of the truck body sidewalls 6, these truck bodysidewalls taper outwardly at an extreme rate, as illustrated in FIG. 3.The tapering of the truck body sidewalls 6 results in the width betweenthe truck body sidewalls 6 at the truck body 2 open rear end having anoutward extension Y on each side in comparison to the width X betweenthe truck body sidewalls at the front of the truck body. Thus, the widthbetween the truck body sidewalls at the rear of the truck body is X+2Ycompared to the width X between the truck body sidewalls at the front ofthe truck body. In one embodiment, each lateral extension Y is between 5to 10% of the width X at the front, such that the width between thetruck body sidewalls is between 10 and 20% greater at the truck bodyrear than at the front. In a preferred embodiment, the width between thetruck body sidewalls at the rear of the truck body is between 10 and 15%greater than at the front of the truck body. As a particular example,the increase in width from the front to the back of the truck bodysidewalls could be about 12%. In absolute terms, depending on the sizeof the truck body, the rear width between the truck body sidewalls maybe at least 36 inches greater than the width between the truck bodysidewalls at the front of the truck body.

The length of the truck body floor 4 is indicated by two differentmeasurements in FIG. 3. The length Z is measured from the back edge ofthe truck body floor 4 to the junction between the front wall 8 and thecanopy 10 of the truck body 2. The length Z′ is measured from the backedge of the truck body floor 4 to the junction between the truck bodyfloor 4 and the front wall 8. To give an example of the size of thebodies exemplified by the truck body 2 in FIG. 3, the typical length Zis about 25-40 feet. The ratio Z/X is (approximately) between 1.25 to1.5. The ratio Z′/X is approximately between 0.85 to 1.15. Minimizing,as much as practical, the body floor 4 length, as illustrated in FIG. 3,reduces the floor area subject to hard rock mined material abrasion.

In a preferred embodiment, the particular dimensions and proportions ofthe truck body can be determined and designed based on the materialbeing hauled. Specifically, the truck body 2 can be shaped anddimensioned to accommodate the correct volumetric load and to maintain aload distribution that results in the center of gravity of the loadbeing proximate a predetermined location on the truck frame 102. Inparticular, the truck body can be designed to locate the center ofgravity of the load at the correct position according to the manufactureof the truck chassis or frame. This can be accomplished by utilizing aload profile that is based on the actual material characteristics andloading conditions present in the specific field haulage environmentswhere the truck body will be used, taking into account factors such asthe cohesiveness of the material to be hauled and the size, shape andgradation of the pieces of material. Thus, the dimensions of the bodycan be customized for the particular material being hauled.

The extreme outward tapering of the truck body sidewalls providesseveral advantages while dumping the load that is being hauled. As thebulk of the load moves towards the rear of the truck body, and thecorresponding opening of the truck body, the load relative to the bodysidewalls 6 recedes away from the body sidewalls. This relative movementof the hard rock mined ore load with respect to the truck body sidewalls6, immediately reduces the contact force between the truck bodysidewalls and the load as the load moves rearward during dumping, andminimizes the likelihood of truck body sidewall abrasion.

In contrast to the truck body sidewalls, contact avoidance between thehard rock mined ore load and the body floor 4 is not possible and theloaded material scrapes over the body floor 4 as the load is dumped fromthe truck body. Therefore, in order to protect the underlying materialthat forms the surface of the body floor 4, the floor is provided with aliner structure 20 that includes a material that is harder than thematerial of the floor surface and, more particularly, harder than thehauled material.

In many instances, the truck body 2 will be used throughout itsoperational lifetime at one particular mining site. In such cases, theliner structure 20 can be particularly selected to provide a hardnessthat is suited for preventing abrasion caused by the particularmaterials being mined at this mining site. Thus, as an example, if thesteel used to form the structural components of the truck body 2 is ahigh strength and relatively high hardness steel having a hardness of450 Brinell, Vickers 480, the unprotected surfaces of the truck body 2will be vulnerable to abrasive wear if the loads being hauled includematerials of higher hardness (e.g., Vickers 480 or higher) than thissteel. Thus, if the loaded materials include magnetite or chert, theliner structure 20 should be advantageously selected to have a Mohsscale hardness greater than 7 and a Vickers hardness greater than 1275HV. For such an application, a suitable liner structure material couldbe chromium carbide, having a Mohs scale hardness around 7.5 and aVickers hardness around 1500. Suitable constructions that provide suchhigh hardness are commercially available and include, for example,Arcoplate® manufactured by Alloy Steel International of Australia or SAS1750™ manufactured by SAS Global Corporation of Warren, Mich.

On the other hand, if the hauled material is harder than the structuralsteel forming the truck body, but not quite so hard as chert ormagnetite, it may be more economical to use a softer liner structurethan chromium carbide, but one that is still hard enough to adequatelyprevent abrasion of the underlying floor surface. For example, if thehauled material included carrolite, having a Vickers hardness between507 and 586, it may be sufficient to line the body floor with a linerstructure 20, formed of a very hard steel of 550 or 600 Brinell (Vickers590 or Vickers 640), to be more cost effective. Thus, the material ofthe liner structure 20, can be specifically selected to cost-effectivelysuit the needs of the particular hauled material to protect theunderlying floor structure.

The liner structure 20 shown in FIG. 4a is formed by a plurality ofdiscrete pieces of lining elements. While it is possible to provide theliner structure 20 as a continuous lining over a large portion of thetruck body floor structure, or over the entire body floor structure 4,such extensive covering is not necessarily required to protect the floorstructure 4, from abrasion. Accordingly, it can be economicallyadvantageous to provide the liner structure 20 in discrete pieces oflining elements 22 that are separated by gaps 24. The possibility ofusing separated lining elements 22 comes from the realization that theabrasion of the truck body surfaces results not from the mere contact ofthe truck body surface with the hard rock ores, but rather from theability of the hard rock materials to slide over a measurable portion ofthe surface as the load is dumped from the truck body. Thus, the liningelements 22 need not cover the entire floor surface being protected, butinstead merely need to interrupt continuous paths of the underlyingsurface, particularly at the rear of the truck body in the longitudinaldirection of the truck body, along which the load will slide when beingdumped.

In the illustrated example, the discrete pieces of lining elements 22are embodied as elongate strips that are approximately six inches wideand spaced apart along the length of the truck body by approximate sixinch gaps. Preferred alternative lining elements could be up toapproximately twelve inches wide and the associated gaps between linerpieces could be approximately three inches. In a preferred embodiment,the gap between lining elements along the longitudinal direction of thetruck body, are no greater than eighteen inches, or more preferably nogreater than twelve inches. Limiting the gap between the discrete liningelements will help prevent long exposed regions of the underlying floorstructure from being abraded by the hard rock materials being hauled.

As a further measure for preventing long exposed portions of the floorsurface, the lining elements 22, preferably have an orientation that issubstantially perpendicular to the longitudinal, or front-to-rear,direction of the truck body. This ensures that there are no long gaps inthe liner structure 20 in the longitudinal direction that could providea path for the hard rock mined materials to scrape along the floorsurface and abrade the structural material of the truck body floor.Thus, while the elongate lining elements 22 can be oriented at an anglewith respect to the longitudinal direction of the truck body, as shownin the herringbone pattern of the lining elements of FIG. 4a , it ispreferred that the elements be oriented closer to perpendicular to thelongitudinal direction than parallel to the longitudinal direction. Inother words, the discrete lining elements, with respect to the elongatedirection of the pieces, are preferably disposed at an approximate angleof between 45 and 90° from the longitudinal direction of the truck body.

In addition to the general surface of the truck body floor 4, the gutter30 at the transition between the truck body floor 4 and truck bodysidewalls 6 is particularly vulnerable to abrasion by hard rock minedmaterials. Accordingly, as shown in FIG. 4b , it is advantageous toprovide transition pieces 26 of the liner structure 20 at anintersection disposed between the body floor 4 and body sidewalls 6.Preferably, the transition pieces 26 are bent so that they may coverboth surfaces of an abutting intersection. In the illustratedembodiment, the transition pieces 26 are provided between the floorstructure itself and a gusset plate 32 that extends between the bodyfloor 4 and adjacent body sidewall 6. Alternatively, if the gusset plate32 is absent, the transition pieces 26 can extend between the body floor4 and adjacent body sidewall 6 directly.

As mentioned previously, the liner structure 20 can be provided byvarious different materials, depending on the different requirements ofthe truck body, particularly the type of material being hauled. Thus,the liner structure 20 could be formed by lining elements 22 composed ofsteel strips of a particularly hard steel that are disposed over thestructural steel of the truck body 2, particularly the body floor 4.Alternatively, if a harder material is needed for the liner structure 20to accommodate harder rock mined materials, the lining elements 22 couldbe formed by backing plate 34 with a material overlay 36, as shown inFIG. 4c . In this particular embodiment, the lining elements 22 areprovided by a steel backing plate 34 with a chromium carbide 36 overlay.The overlay can be applied to the backing plate by various methodsincluding welding or fusing (fusing being the preferred method) thechromium carbide overlay to the backing plate. Each lining element 22 isattached to the surface of the body floor 4, for example by welding, toprovide a surface that is strongly protected from wear. It is alsopossible, as an additional alternative, for the overlay to be applied tothe floor surface directly. This is particularly feasible if the overlayis provided on the floor components prior to fabrication of the truckbody.

In many embodiments the area in which the liner structure 20 is providedneed not cover the entire interior of the truck body 2. In particular,the body sidewalls 6 can be mostly or entirely free of the linerstructure. Likewise, a portion of the front of the truck body floor mayalso be free of the liner structure 20. The liner structure 20 may beunnecessary on the body sidewalls due to the abrasion avoidanceresulting from the outward taper of the body sidewalls, as describedabove. Thus, for example, if the truck body 2 includes a gusset plate 32at the intersection with the body floor 4, the body sidewalls 6 may beentirely free of liner structure 20 and the associated lining elements22. On the other hand, if the body sidewalls 6 and floor 4 intersectdirectly, it may be advantageous to include transition pieces 26 of theliner structure 20 that spans the body floor 4 and the body sidewalls 6.However, in such a case, it can still be possible that the bodysidewalls 6 are free of any lining elements 22 that exclusively coverthe sidewalls 6. Thus, the lower portion of the body sidewalls 6 wouldonly be covered by transition pieces 26 that are shared with the bodyfloor 4. Of course, it is also possible for the liner structure 20 tocover a portion or the entirety of the body sidewalls 6.

The front portion of the truck body floor 4 may also be less susceptibleto wear, and thus designed to be free of the liner structure 20. Whilethe front portion of the body floor cannot entirely avoid slidingcontact with the hauled material, a considerably smaller portion of eachload will pass over the front portion of the truck body floor 4.Accordingly, compared to the rear of the truck body floor 4, the frontof the truck body floor can be substantially less vulnerable toabrasion. For this reason, up to the front 25% or up to the front 75% ofthe truck body floor 4 may be free of the liner structure 20, as shownin FIG. 4a . Alternatively, the liner structure 20 may extend over anarea covering the entire length of the truck body floor, as shown inFIG. 5.

Aside from the herringbone configuration of the liner structure 20 shownin FIGS. 3-5, the liner structure 20 could be configured in variousalternative patterns, as shown in FIGS. 6 and 7. For example, in FIG. 6,the liner structure 20 is provided in strips that extend across anentire width of the truck body floor 4. As illustrated, these longstrips can be formed by individual lining elements 22 with abuttingends. FIG. 7 shows another alternative pattern of the liner structure 20including lining elements 22 that are spaced apart from neighboringlining elements along the longitudinal direction of the truck body 2,but offset and overlapping with adjacent lining elements in the lateraldirection.

In addition to the abrading that can occur as truck bodies haulextremely high hardness hard rock ores, these same ores may in certaincircumstances contain considerable impurities which may cause the hauledmaterials to amalgamate and stick to surfaces of the truck bodies 2.This sticking of material typically starts in the front corners of thetruck body and then progressively extends to build and transgressrearward from the front corners of the truck body. To combat thisphenomenon, the truck body 2 can include a non-stick surface 40 bridgingthe intersection of the truck body floor 4, one of the truck bodysidewalls 6 and the truck body front wall 8. It should be understoodthat the intersection of the truck body floor 4, truck body front wall 8and opposite truck body sidewall 6 can also be bridged by a mirror-imagenon-stick surface 40. In this context, the term bridging is used toindicate that the non-stick surface extends from one of the truck bodycomponents (i.e., floor, sidewall or front wall) to another. This can beachieved by one or more distinct plates with a non-stick material thatextends across the intersections and abuts each of the correspondingtruck body components, as shown in the FIG. 8, or it can be achieved bya surface section of the truck body components, near the intersection,being covered with a non-stick material. The use of distinct plateshaving a non-stick surface may be advantageous because the distinctplates can cover the intersection between the truck body components, andthus avoid the geometry of a sharp edge between two components or adistinct corner between all three components. This is advantageousbecause sharp edges and corners are more likely to capture materialbeing hauled and provide a starting point for material sticking to thetruck body, i.e. “carryback.”

The term non-stick surface is used herein to encompass hydrophobicsurfaces and/or oleophobic surfaces. The term hydrophobic refers to anysurface, such as a treated steel or a painted surface, on which waterbeads are formed when water contacts the surface. A hydrophobic surfaceis exemplified by poor wetting, poor adhesiveness and having a ‘low’free surface energy/adhesion. Relative terms are used to indicate thedegree of hydrophobicity of a material or surface, where surfaces withwater contact angles greater than 90° are called hydrophobic whilesurfaces with water contact angles greater than 150° are calledsuper-hydrophobic. Just as water is repelled by hydrophobic materials,so can oil and petroleum products be repelled by oleophobic andsuper-oleophobic materials or surfaces. The non-stick surface describedherein can be hydrophobic, super-hydrophobic, oleophobic,super-oleophobic or any combination thereof. Various differentconstructions can be used to make the hydrophobic or oleophobicnon-stick surface. For example, prefabricated hydrophobic plates, suchas CRODON® steel plates manufactured by Chromium Corporation of Dallas,Tex., can form the non-stick surface coated plates, which is thenattached to the existing components of the truck body 2.

Embodiments of the invention also include methods of designing andfabricating the hard rock mined ore truck body as well as transportinghard rock mined ores using a vehicle equipped with the truck body.

FIG. 9 is a flow diagram illustrating a method that includes steps forboth providing a vehicle with a truck body that is configured forhauling hard rock mined ore materials from a loading site to a dumpingsite.

In addition to the construction of a general truck body that isconfigured for hauling material having a hardness that is greater thanthe structural steel components of the truck body, which includesproviding the truck body with extreme tapered body sidewalls and a linerstructure, as depicted at 78 in FIG. 9, the truck body can also becustomized in design and construction to carry a particular material. Inthe method for creating such a truck body, certain characteristics ofthe material are first determined, including a hardness characteristicand a load profile characteristic, as shown at 70 and 72. For example,if the material is homogenous, a value of a particular hardness scalecan be determined for the material, or if the material includes variouscomponents, a hardness value of the hardest component can be determined.Exemplary load profile characteristics that might be determined includethe angles of material repose that are formed when the material isloaded and hauled and the size and shape of a plateau that forms on thetop of the load of the material being hauled.

Based on the determined hardness characteristic, if needed anappropriate minimum hardness for the liner structure can be determinedthat is greater than the hardness of the material being hauled. Usingthis minimum hardness value, an appropriate material can then bedetermined if needed for the liner structure at 74. Likewise, using theload profile characteristics in combination with the vehicle capacity,the size and relative dimensions of the truck body can be calculated toefficiently load and transport the load in the truck body 2 with theselected material at 76. Once the design of the truck body having theextreme outwardly tapered sidewalls is completed, the truck body can beconstructed and if needed the liner structure mounted on the surfaces ofthe truck body at 78, particularly the body floor. In an alternativeembodiment, the liner structure can be provided on portions of the truckbody particularly the body floor before final assembly of the truckbody. Finally, the truck body 2 is mounted on the chassis of anappropriate vehicle, such as an off-highway truck, at 78.

The constructed vehicle can then, haul and dump the particular materialsthat it was designed for. First, at 80, the truck body is loaded withthe hard rock mined ore at a loading site within the mine site. Thevehicle then transports the load, at 82, to a dumping site where theload of hard rock mined ore will be unloaded from the truck body. At thedumping site, the truck body is raised at 84, for example usinghydraulic cylinders 108 about a pivot point 106 as shown in FIG. 2. Thelifting of the truck body 2 causes the load to slide out of the truckbody at the rear thereof. Wear of the truck body during the unloadingprocedure is avoided because the load is laterally released from thesidewalls of the truck body 2, at 86, due to the outward tapering of thetruck body sidewalls, which prevents abrasion of the truck bodysidewalls. Abrasion of the truck body floor is also prevented, at 88,because the truck body floor is protected from abrasion by the linerstructure 22 as the load is dumped.

While the invention has been particularly shown and described withreference to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention.

The invention claimed is:
 1. A method of custom designing, fabricatingand using a truck body in a mining site, the method comprising:determining hardness characteristics of an earthen material at themining site to be hauled; selecting a material having a hardness greaterthan the hardness of the earthen material to be hauled by the truckbody; lining a floor of the truck body with the selected material, wherea material comprising the floor has a hardness less than the hardness ofthe earthen material; loading the truck body with the earthen material:pivoting the truck body upwardly to dump the loaded earthen materialfrom the truck body; releasing lateral confinement of the loaded earthenmaterial in the truck body as the loaded earthen material dumps from thetruck body as a result of the loaded earthen material receding fromflared body sidewalls of the truck body, thereby inhibiting abrasion ofthe flared body sidewalls by the earthen material; and protecting, bythe lining, the floor of the truck body from abrasion as the loadedearthen material moves along the floor of the truck body as the earthenmaterial is dumped.
 2. The method recited in claim 1, wherein lining thefloor includes arranging a plurality of discrete pieces of the selectedmaterial over a floor surface.
 3. The method recited in claim 2,including spacing the plurality of discrete pieces such that a gap isformed between adjacent pieces, which exposes the floor surface.
 4. Themethod recited in claim 1, wherein lining the floor with the selectedmaterial includes lining the floor with a chromium carbide overlay. 5.The method recited in claim 1, wherein a majority of the flared bodysidewalls are free of any lining.
 6. The method recited in claim 1,including providing a gusset plate at an intersection between each ofthe flared body sidewalls and the floor, and providing transition piecesas part of the lining of the floor that extend from the floor to thegusset plate.
 7. The method recited in claim 2, including distributingthe plurality of discrete pieces such that each of the plurality ofdiscrete pieces extends in a direction that is along an angle between 45and 90 degrees from a longitudinal axis of the truck body.
 8. The methodrecited in claim 5, wherein an entirety of the flared body sidewalls arefree of any lining.